Ignition device



March 27, 1956 s, UDALE 2,739,582

IGNITION DEVICE Filed Oct. 9, 1953 IN VEN TOR.

United rates Patent IGNITION DEVICE Stanley M. Udale, Detroit, Mich., assignor to Holley Car-' buretor Company, Detroit, Michigan Mich., a corporation of The object of this invention is to advance the spark on an internal combustion engine: (a) as the speed increases; (b) as the load decreases, and to blend the two variables so that no condition can normally arise in which the engine will knock due to an overly advanced spark. On the other hand, it is desirable to avoid an overly retarded spark. There is a sufiicient range between so that a commercial solution is possible. In fact, the spark can be retarded quite a few degrees without overheating or unduly increasing fuel consumption.

The solution is:

This invention briefly comprises an engine operated compressed air pump which generates a pressure which increases with speed. This pressure is modified by a metered air leak which leak increases as the throttle is opened and the manifold air pressure increases. The spark thus responds to both speed and manifold air density. The needle valve controlling the air leak can be made of such a shape as to give the desired sparkload-speed characteristic.

The figure shows diagrammatically the preferred form of my invention.

is the air entrance, cleaner, to the carburetor 12 16 is the inlet manifold.

18 is a passage from the inlet manifold 16 to a chamber 20.

Inside the chamber 20 is partly exhausted, bellows 22.

24 is a needle valve controlling a restriction 26. 25 is the escape outlet for compressed air controlled by the needle valve 24.

Atmospheric pressure through a pipe 11.

A T-shaped pipe 28 has to the left a pump outlet through a restriction 36 and a restriction 26 to the right. The third arm of the T communicates the pressure between the two restrictions 26 and 36 to the chamber 30.

35 is the diaphragm to the diaphragm chamber 30.

The pressure in this diaphragm chamber 30 is determined by the speed of operation of pump 32.

Pump 32 is driven by the shaft 38 which also drives the circuit breaker cam 40 and the high tension element 44 shown in broken lines.

46 is a rod operatively connected to the diaphragm which rotates the circuit breaker plate 48, a circuit breaker pivot 49 carrying circuit breaker arm 47 around the outside of bushing 50.

The inside of bushing 50 serves as a bearing for the shaft 38. The circuit breaker arm 47 is operated by the cam in a well-known manner.

The pump 32 is the subject of a co-pending application Serial No. 352,415 filed May 1, 1953, by Eugene C. Bettoni and Kalin S. Johnson and now abondoned.

Briefly a pair of rollers 52-54 mounted on a crossshaft 56 driven by a drive shaft 38 ride on a cam surface 58 (shown in broken lines). This cam rides on an preferably including an air controlled by the throttle 14.

mounted an exhausted, or

is derived from air cleaner annular plate 60 which is supported by the spring 64 under the flexible diaphragm 62.

Hence, as the shaft 38 rotates, then the diaphragm 62 reciprocates. A tongue and groove joint 66 connects driven shaft 68 with driving shaft 38. Driven shaft 68 carries the driving means for high tension distributor 44 (shown in broken lines) driven by the fiat spring 42 mounted on the end of shaft 68.

74 is the outlet valve.

72 is a spring seating the valve 74.

34 is a similar spring loaded inlet valve.

11 is the inlet air passage from the air cleaner 10 to the inlet valve 34.

Operation With the throttle 14 wide open and the engine under heavy load no spark advance is desired. This result is gained as practically atmospheric pressure acts on the bellows 22 through the passage 18 from the manifold 16. The needle valve 24 is therefore moved to the right. The pressure in the chamber 39 falls and the spring 33 moves the diaphragm 35 over to the right (as shown). As speed increases-as the load is decreased (as the crest of the hill is reached, for example) some spark advance is desired. This is gained as follows:

The increased speed causes a slight drop in pressure in the manfold 16 so that the valve 24 moves slightly to the left. The volume of air discharged past this valve 24 increases greatly so a pressure builds up between the two restrictions and the diaphragm 35 moves to the left.

To check speed the throttle 14 is moved towards the closed position, the pressure in manifold 16 drops and the bellows 22 expands. The valve 24 moves to left and restricts the opening 26 so that the pressure between the two restrictions 26 and 36 increases. The pressure to the right of the diaphragm 35 increases greatly and so the spark is fully advanced which is the desired result.

The movement to the ignition by rotating the 49 on which oscillates the well known manner What I claim is:

In an ignition system for adjusting the timing of an internal combustion engine, a drive shaft driven by said engine, an air pump operated thereby having an air entrance and a restricted air exit, a circuit breaker, a plate supporting said circuit breaker, a cam driven by said engine and engaging said circuit breaker, a diaphragm, a link from said diaphragm to said plate, a spring rotating the plate, a diaphragm chamber enclos ing said diaphragm, a passage from said chamber to the exit side of said pump on the upstream side of said restricted exit so that the pressure in said diaphragm chamber rises as the speed of the engine increases so that the spark is advanced, and in which there is an inlet manifold and a throttle valve and in which there is a valve located in said restricted air exit to restrict the exit of air from said air pump, means responsive to inlet manifold suction to move said valve toward its restricting position so that the pressure in said diaphragm chamber rises whenever the engine throttle is closed.

left of the rod 46 advances the plate 48 which carries the pin the circuit-breaker arm 47 in now in universal use.

References Cited in the file of this patent 

